Tuesday, 19 July 2011

The present debate is about the legal status of cannabis. The topic is not itself whether smoking cannabis is an especially good idea, or the kind of thing everyone should do, or harmful, or beneficial. None of these will decide the question of legalisation and prohibition, certainly not on their own.

I do not believe any harmful effects to the user that might plausibly be discovered would be a sufficient justification for bringing to bear the power of the state to criminalise the possession and use of cannabis. Nonetheless, for those who disagree or whose attitude to cannabis has otherwise been shaped by highly exaggerated warnings, I've explained my reasons for thinking that the mental health risks from taking cannabis are minimal. I don't propose to go into those any further here.

The first issue I'll deal with is the burden of proof - in the first place, it seems clear to me that any exertion of state penal power over the individual requires justification. Hitchens advocates instituting a much harsher punitive regime than the present one, which already imprisons, fines, and brands as criminal a large number of users. One might suggest that the status quo is privileged, that any departure requires positive justification, but that need not concern us since neither Hitchens nor I consider the current position acceptable.

The 'precautionary principle' - that where it seems possible that a course of action may cause harm, the course should not be adopted - is of little help here - or for that matter in general - since unless unfounded fears are allowed to prevent any change, the 'possible' harms must in fact be probable to a sufficient degree, and since there will be pros and cons on both sides, the question rapidly becomes - which is to be preferred? The harmful effects of the present regime, and of the much harsher regime Hitchens advocates, are clear - imprisonment is a major harm in itself to individuals and those close to them, and while relatively few may be prosecuted, many more take furtive and burdensome steps to avoid it - which accounts on large part for the relatively low rate of conviction. And those who do not share the conviction that cannabis is an innocent herb may not appreciate the resentment, and perception of victimisation that this involves.

I've previously mentioned the harmful effects of the lack of regulation which comes with less-than-completely effective prohibition. These would occur even if possession and use were to be entirely decriminalised. Criminal gangs and unscrupulous dealers will sell to any age group and freely adulterate a product which in any case cannot be checked for strength or specific constituents (for example, one might wish to ensure that one's cannabis contained a relatively high proportion of cannabidiol).Hitchens saysIf it is right for the substance to be illegal (the core of the argument) then it is right for the law to punish its possession. We are not talking about freedom of speech or thought here.

But from this we may also conclude that if it is not right for it to be punished, it is not right for it to be illegal. Punishability and illegality in the present sense of the word are inseparable. One may decide that possession of the substance would best be eliminated, and from that conclude that it should be criminal, but that is a highly dubious move. A very obvious issue is whether legalisation would increase cannabis use from current levels. To Hitchens this may be somewhat irrelevant, since he seems intent on ramping up the penalties and the detection effort so as to eliminate cannabis use and traffic. I have no doubt that this could be done - but I repeat my question to PH - just how far would we need to go to achieve this?

For one thing, as well as punishment, criminalisation requires detection. Serious attempts to wipe out cannabis would surely require extreme intrusions into personal privacy, such as drug testing, sniffer dogs at every corner, stop-and-search, and destructive search of the homes of those merely suspected of possession. As well as being intolerable, this would of course be very expensive (as is foregoing the tax revenue which might be gained by legalising trade in cannabis). the problem is that for all Hitchens's talk of wider social effects, impacts on family, and so on, cannabis possession and use is objectively speaking a very private business. There need be no victim to report it, no very easily detectable effects in the public space. Cannabis use is unobtrusive, and detecting it is accordingly intrusive.

It is worth mentioning that the present system, under which scarce police and court resources are not directed toward cannabis users as a matter of priority, mitigates some of these harms to a degree, at the expense of a good deal of arbitrariness and discretion on the part of the authorities - and unequal treatment is very likely to penalise the poor and the marginalised, indistinguishable as they are on inspection from those utterly alienated members of the socially excluded underclass whom many rank and file police openly regard as 'scum'. Those minorities for whom driving a BMW tends - still - to provoke suspicion rather than deference among the police will of course tend to find that they are disproportionately harried. Such functional harassment may sound trivial to those who don't experience it, but the daily drip-drip of humiliation and obstruction is very far from trivial.

(There is one possibility which seems interesting and arises from taking to its conclusion the idea of cannabis use as a private matter. It would be possible that non-commercial cultivation for personal use be entirely legalised, while trading in cannabis remained illegal. Private individuals could, on this model, purchase properly labelled and regulated cannabis seed and cultivation equipment, content testing kits, perhaps even lockable growing units analogous - though the parallel is overblown - to gun cabinets. This could have some advantages in addressing the concerns of those with whom I disagree, and thus enabling a consensus position, and might even have other advantages. Or it might be utterly unsustainable. This is so speculative and underdeveloped a position that I'll leave it hanging for now, possibly revisiting it later.)

Leaving aside the unsatisfactory status quo, I repeat, there should be a presumption against prohibiting any conduct, which can be overturned only given a good reason to do so. Hitchens seems to have misunderstood my earlier statement of this principle, responding I don’t think, as Mr Wilkinson implies, that we are naturally lawful creatures. I start from a willing acknowledgement that there will have to be laws. The point is, which laws?

In deciding if there is a good reason to prohibit, we can't ignore the impact of prohibition. If we are to look at harmful outcomes, we must look at them in the round, including the consequences of trying to deal with them. We must also weigh harms against benefits.

One point which I think is not really answered by Hitchens is that of paternalism. As an opponent of nannying, interfering government action, one would suppose that he should be opposed to people being prohibited from doing thing which need affect only themselves. One rather thin response is I don’t mind being called ‘paternalist’, as I think drug-takers are largely infantilised by their pitiable habit, and need a parental hand. I read this as saying that while paternalism is not in general an adequate basis for punitive measures, in this case it is, because of the childlike nature of cannabis takers. I'll not dwell on the merits of that argument.

The other tack is to bring in actual children - or at least adolescents - and argue as follows: their own cannabis use is a source of very significant harm, they are not capable, or not to be trusted, to decide for themselves, and that their gaining access to cannabis can only be prevented by prohibiting all possession of cannabis. The prohibition of cannabis to consenting adults is thus presented as a side-effect of protecting children, or more plausibly, adolescents.

We are now in the realms of a social cost-benefit analysis, with potential harms to children factored in and suitably weighted. If this is the right way to look at the issue of social harm - and I think it has to be - Hitchens's position amounts to a claim that the risk to teenagers is sufficiently large and grave to outweigh ill-effects of prohibition, including foregone benefits.

The enjoyment of cannabis use must feature in any consideration of costs and benefits, as must the freedom to choose whether to make use of this natural substance (it could after all be grown and consumed entirely in private and without affecting anyone else at all). It's all very well for Hitchens to disapprove of cannabis use - but his attempt to pick and choose between pleasures is not convincing As I've suggested, enjoyment of cannabis is certainly not limited to, nor even mainly constituted by, mere empty pleasure or euphoria - though in any case, it's a rather Spartan approach to suggest that a bit of pleasure counts for nothing at all. We will need some reason to think that the benefits of cannabis are of no value at all.

In his first response, Hitchens stated:

I believe there are people who enjoy mistreating animals. For all I know they say it enhances their appreciation of art, food , music and sex, and stimulates creativity - though I haven’t a clue how one would measure any of these things anyway. I couldn’t care less. Their pleasure in this activity is of no interest or consequence in any discussion of what the law should say about cruelty to animals.

And no, I am not comparing cannabis smoking to cruelty to animals, merely demonstrating that the point is irrelevant.

But of course the entire point is to compare (not necessarily equate) cannabis smoking to cruelty to animals. The reason why the fictitious benefits of animal cruelty are not regarded as relevant is that cruelty to animals is so bad, or an evil of such a kind, that it either hugely outweighs or 'trumps' the benefits that in Hitchens's thought experiment might be derived from it. But of course, cruelty to animals - in animal testing, meat production, even fox hunting and other blood sports, is regarded by some (if they are honest about what is involved) as capable of being justified by benefits - not necessarily very major ones - to humans. Of course, one may very well disagree with that view - or maybe the idea here is that sadistic pleasure in particular is the evil which trumps any benefits. But in either case, exactly what the corresponding evil is in the case of cannabis remains to be seen. The position that taking cannabis is evil in itself and cannot be tolerated will be dealt with separately.

This seems as good a point as any to address two issues which arise from posts made by Hitchens which, while not addressed to me as part of this exchange, have been posted since it began.

No serious drug could be administered in the forms in which cannabis is taken by those who use it for pleasure. There are, on both sides of the Atlantic, drugs made from THC (but which do not provide a high) They are rarely prescribed because they simply aren't very effective. (Nabilone is the main one in Britain).

This is interesting: the synthetic version of THC (not made from THC) - which supposedly lacks the relatively benign side-effect of a THC high - is, apparently, ineffective, but the effective form of the drug could never be licensed. If that is the case, then the only way in which people can get the undoubted medical benefits of THC is by self-administering the substance, as is done with various other herbal remedies that are available without prescription.

In that case, the medical benefits of cannabis are no longer irrelevant to the legalisation debate, but provide a very important - overriding, one might think - positive benefit of legalisation.

I am though only going by Hitchens's remarks, which do not consider an alternative explanation for cannabis/THC not being licensed: the pharmaceutical industry can't patent it, and rightly see it as competing with other lucrative products, which might also explain why Hitchens has the impression that Nabilone has no 'high' (it does have advertised side-effects which seem remarkably similar to a high, as seen by medical science) - the absence of a high is the USP (unique selling point) of synthetic or semi-synthetic - patentable - chemicals. (I'm not quite sure of this point, since I understand there has at least been some attempt to patent THC. I've not had time to check this as yet.)

The point that someone from NORML once suggested that publicising medical properties of cannabis could work to improve the general image of the substance (which has after all been under sustained and unscrupulous attack for many decades) doesn't seem to me to be of much interest. Now if a trusted source of presumptively neutral information, such as a scientist involved in research on the subject were to make it clear that he was in the business of producing propaganda, that would be a different matter. An advocate acknowledging, in a rather naive way, the rhetorical aspects of the debate and the importance of image, not quite so important.

Reefer Rage

Hitchens has also provided a list of news stories (High and Violent) which purport to show a new - rather desperate - suggestion for a harmful effect of taking cannabis - that it has a more than negligible chance of triggering a violent attack.

I think it very funny that an unadorned recitation ('High and Violent', posted on Thursday afternoon) of a few factual stories from several newspapers over the last few years, the fruit (as clearly stated above) of a brief search, making no wider claims than that the image of cannabis as an invariably peaceful drug is questionable, should have aroused the excited storm of spittle from the drug lobby which we see here.

The brevity of the search is of course irrelevant - searching the internet is a fast business. But such a search is cherrypicking anecdotes from among cherrypicked anecdotes. A few such accounts give no indication of prevalence - but the fact that the stories are considered newsworthy gives some indication. Of course, a single or very small number of confirmed instances could prove that a violent reaction to cannabis is possible - but for that one story would do (in fact the form of most of the news stories is 'violent person - either insane or under the influence of alcohol or major drugs - subsequently found to have taken cannabis'. This is not exactly scientific, is it. And even if all of these examples were actually shown to be of cannabis-induced murder, the incidence would be vanishingly small compared to the death and destruction caused by cooking at home, for example. But like terrorism scares, scares about this kind of incident have a much firmer grip on the public mind and produce a hugely disproportionate response.

I wonder what other things one could find to have coincided with nastiness ten times in as many years? I wonder what the papers would be like if instances of those high on cannabis helping old ladies across the road were considered news? And I wonder if driving under the influence - which would of course remain illegal - should really be classified as 'violence'?

I don't think this line of argument merits further consideration.

Social cost-benefit calculation

Hitchens's strongest remaining consequence-based argument for comprehensive prohibition seems, as I suggest, to be harm to young people. I've already provided my reasons for regarding the mental health risks as highly exaggerated if accurate at all, and any risk there may be should certainly be discounted heavily since the legalisation case allows for criminal penalties for supplying such psychoactive substances to minors (I wonder whether caffeine, a powerful stimulant for all that it is largely non-euphoriant, should be subject to this kind of regulation).

http://hitchensblog.mailonsunday.co.uk/2011/07/think-it-possible-that-ye-may-be-mistaken.htmlI might add Allan Bloom's point in 'The Closing of the American Mind', to some extent backed up by Tim Lott in 'The Scent of Dried Roses', that those who have achieved exaltation through drugs in early life are left afterwards with an emptiness, a flatness, an absence of the superlative, which stays with them all their lives. I have a strong suspicion that the human body has only a limited capacity to deliver the sensation of joy, and that the use of drugs eventually exhausts it, with sad consequences for the individual...there are good rational and material justifications for restraining unwise and impulsive young people from consuming chemicals which might - unexpectedly and irreversibly - drain all the colour out of their later lives.

I don't consider this a clear enough case of harm to carry much weight. Even if it is broadly accurate in the sense that intense experiences may make subsequent ones seem less intense by comparison, thisapplies to anything, not just drugs. I don't accept the 'limited supply of joy' hypothesis at all.

But what of other harms that might be associated with cannabis use among teenagers? Habitual cannabis use during the school day, is certainly going to interfere with learning, for example. And there may be other harms from taking cannabis at a young age. How widespread heavy cannabis use under the age of, say, 16 actually is, I don't know, but as Hitchens would no doubt - plausibly - point out, it may be expected to affect the poorest and most disadvantaged in society much more than others. I think that we would expect playground cannabis-smoking to be a feature of more deprived areas rather than affluent and comfortable ones. Again, my approach to this is to ask why that should be.

I return to an issue which I've raised in a different connection - the idea of cannabis as a kind of viral infection, an exogenous influence, an uncaused cause. This is wrong. Even teenagers are not helpless in the face of the evil weed, and there are more basic determinants of heavy cannabis use - rebellion, despair, alienation, boredom, which need to be addressed directly and which cannabis use adds only to a relatively minor extent. When Marx spoke of the opium of the people, he was referring to the painkilling, not euphoriant, properties of opium. In any case, I still doubt the ability of any likely prohibition regime - and certainly the current regime - to do a better job of keeping cannabis away from the under-age than legalisation with strict penalties on supply to minors would do.

Hitchens claims that those advocating legalisation - or opposing increased and more consistently enforced penalties - are greasily selfish dope-smokers who believe that they are not vulnerable to reefer madness, yet are willing to put others at risk of it. (I know for a fact that some legalisation advocates don't take cannabis themselves, but no doubt most campaigners do use cannabis at least sometimes. If they didn't, a different personal attack could be mounted, accusing them of advocating something they are not 'willing' to take themselves.)

I've made my opinion of the reefer madness claim pretty clear already, so I think this argument fails basic factual checks. But since we are operating at this level of rhetoric, I would point out that - like most authoritarian views - the prohibitionist outlook is also 'selfish': the non-cannabis using prohibitionist (surely a majority of prohibitionists are not users) has little to fear - fit-ups and mistakes excluded - from punitive measures for cannabis possession, while being eager that others should face them. No doubt the prohibitionist considers that punitive measures are deserved by the 'giggling', irresponsible dope-smoker, but if so, some arguments need to be provided that cannabis use is wrong - to the extent of being punishable by law without regard to the consequences for the convicted person. I will deal with that issue in the following, final, post.

On the topic of hypocrisy and self-serving arguments, the issue of alcohol is worth revisiting. Ronald Reagan in one of his drug-war speeches exemplified this. Recognising that his generation had recourse to large doses of gin ('Martinis') as a socially acceptable 'crutch', he raised the putative complaint from the younger generation that cannabis was simply their equivalent. His answer - that he would prefer it if this generation didn't 'need' any 'crutch' at all. That's easy for him to say - before approximately 6.15pm, at least.

Leaving aside the characterisation of either gin or cannabis as a 'crutch', the hypocrisy argument is not purely a negative point-scoring exercise. For one thing, the social effect of such hypocrisy is corrosive, and means that the consent of a substantial proportion of the governed will be withheld, making the law against the almost indetectable crime of cannabis possession almost impossible to enforce. For another, it tends to suggest that those applying a double standard do not in fact believe their own arguments, but rely instead on prejudice, which of course tends to undermine their persuasiveness a touch.

The most important consequence of the double standard, though, is this: if cannabis is to be banned, then so is alcohol. But alcohol is not to be banned - as all involved in the debate clearly in fact agree. The inescapable conclusion is that cannabis is not to be banned either.

I've already, like Reagan, suggested that cannabis can supplant alcohol as a means of altering consciousness. Reagan's reply is 'do as I say, not as I do'. Hitchens does not take that approach:

For further clarification I'll consult an older post - though I recognise that Hitchens may not still hold precisely the same views, since he is, to his credit, willing and able to change his mind:

http://hitchensblog.mailonsunday.co.uk/2010/09/a-letter-from-merseyside-and-a-few-notes.html:
...As I have many times said, I would willingly give up the small amount of alcohol which I drink, if I believed that by doing so I could help protect others, less able to exercise self-control, from its many wicked effects. I just don't happen to think that my sacrifice would achieve anything of the kind, and so prefer to proceed along the lines of restricted sales, tough licensing laws and the religious re-education of the people (as took place both in Protestant England and Roman Catholic Ireland in the 19th century) which would lead necessarily to greater temperance.

I have every reason to think that Hitchens means what he says here - but few others do. And even Hitchens is quick to conclude from this 'cultural embedding' that the only alternative is a system of regulation basically the same as the current one (or the very similar one which was in place before all-day licensing was introduced a few years ago), along with education.

Unlike cannabis, which is not legal and is not part of our culture, alcohol has been legal in this country for many centuries, many people use it in moderation, and it is perfectly possible to consume it without stupefying yourself.

I'm assume Hitchens has some specific point in mind here as to the precise significance of long-standing legality, but rather than provide my own elaboration of what that might be, I'll ask him to clarify, and simply add that of course that something is already legal or illegal cannot in itself provide a justification for its continuing to be.

It is of course also possible to smoke cannabis without stupefying yourself, as I pointed out in the opening post of the debate. The degree of intoxication experienced from consuming cannabis, just as much as from taking alcohol (and let's not pretend that the intoxicating effect of a single alcoholic drink is either non-existent nor a large part of the motivation for drinking the stuff) is controlled by dose, which is controlled by the person taking it. And most people who smoke cannabis do so in relatively small doses. Of course under legalisation and regulation, cannabis dosage could be controlled and sensible doses would be standardised. Smoking extra-strong joints might well come to be as frowned upon as drinking Special Brew or what's known in Glasgow as electric soup.

The effects of cannabis, I may as well point out, are not simply to stupefy, any more than they are to provide pure pleasure (opiates are perhaps the closest common drug to doing that). Cannabis has complex and often subtle effects. The individual effects and pharmacodynamics of the active constituents present in various proportions in cannabis and its smoke are not very well understood, but typically lower doses of cannabis tend to provide the experience if anything of being more sensitive to many things, not less so, and to stimulate rather than suppress thought.

Cultural embedding might include established traditions for sensible use - though the British have never been renowned for great temperance in the use of alcohol, perhaps tending to rely on the low alcohol content of ale to regulate use where our Mediterranean cousins have been used to wine, or perhaps requiring more in the way of intoxication to see them through the cold months. In any case, there is clearly a distinct lack of moderation in its use among a sizable proportion of the population. And Hitchens acknowledges that education and training is required in sensible use of alcohol. But even if such education takes effect, this provides a reason why prohibition may not be required. Cultural embedding is supposed to be a reason why prohibition is unworkable.

I don't think an appeal to socialisation and pub culture is necessarily going to make all the difference, either. Pub culture has been substantially damaged by banning smoking, especially in premises which for one reason or another are unable to provide surreal 'virtual saloons' complete with canopy, sofas and extremely wasteful mushroom heaters. It's further been transformed in many cases by an increased emphasis on food, and of course city-centre standing-room-only megapubs are an innovation.

I suppose the idea, stripped of the impressive resonance of the term 'cultural embedding', is a root just that if alcohol were to be banned tomorrow, there would quite possibly be riots and certainly a huge backlash. But this does not rule out a more gradual approach, such as Hitchens perceives the progressive marginalisation of tobacco to be - though he does not appear to suggest that tobacco will eventually be outlawed altogether. A phased approach could also be taken to legalisation: in general, problems of transition are surmountable given a little imagination and forethought.

As Hitchens says:

http://hitchensblog.mailonsunday.co.uk/2011/07/prohibition-blues.htmlAs for ‘following rather than leading public attitudes’, I do not know how old Mr Wilkinson is, but my conscious life has more or less spanned the period in which cigarette smoking has moved from being normal and accepted to pariah status - and the period during which drunken driving was severely discouraged by moral pressure and law (law being far more effective). In both cases, the authorities spent a great deal of time and money changing attitudes. Plenty of people refused to accept that it was wrong to drink and drive, for many years after it was obviously so. It was many years before Richard Doll’s first report and a general acceptance in society that smoking was likely to lead to serious health dangers. In both cases the government had to ‘lead’ public opinion, not follow it.

And this is consistent with the comments of mine to which it was a response: my point was that criminalisation has to follow rather than lead public attitudes - how those attitudes are shaped is another matter. the same does not apply to legalisation. the public do not have to be convinced that something is a great idea for restrictions on it to be lifted - of course they should probably not be under the true or false impression that the lifting of restriction will impose a significant cost or burden on them, and in the case of cannabis they need not.

But perhaps there is something about alcohol that makes it harder to convince people to give it up than nicotine? I don't think we have far to look for what that might be: a substantial mind-altering effect. It may well be that people have - and will always have - a desire or felt need to alter their state of consciousness in one way or another, and indeed to do so by the use of intoxicants. Perhaps this basic human motive could be satisfied by training in meditative and similar techniques - though I'd like to think that Hitchens would find this more creepy - certainly if it were a state-run programme - than recourse to intoxicants, which at least have some element of spontaneity and sociability.

If this approach is correct - and without pretending that my unsubstantiated opinion is persuasive, I'd say it certainly seems plausible - then the debate takes on rather a different complexion - and we may find that all we have is a choice between different intoxicants. I've already suggested that cannabis and alcohol are in large part competitors for peoples' leisure time. To this we may add the other major street drugs - and of course prescribed pharmaceuticals, which might thus be revealed as being in competition with cannabis not only for the market in those effects standardly attributed to 'medical marijuana', but also the lucrative market in antidepressants and other psychoactive medications widely prescribed, in particular by GPs on the basis of a 15-minute consultation and a stockpile of subliminal logos which they see very deliberately emblazoned over the freebie notepads, pen and sundry items which they are equally deliberately showered with by the drug companies.

Which leads tolerably neatly to the last (I have probably missed some) of the general, broadly consequentialist, considerations Hitchens presents as militating against legalisation, and in favour of heavier penalisation, of cannabis: the Huxley gambit.

This is of course not the Aldous Huxley of the Doors of Perception and Heaven and Hell, but the Aldous Huxley of Brave New World:

This is pretty heavily hyperbolic: permitting 'self-stupefaction' does not have as a logical - nor even inevitable - consequence anything like 'Brave New World'. But there is a point here - doesn't recourse to recreational drugs such as alcohol, chocolate and cannabis tend to make people less dissatisfied, less angry, less likely to rise up in revolt? Probably.

We are more passive, less free, more subservient. more conformist and less critical than we used to be.

I'm not sure when this golden age of bold individualistic iconoclasm is supposed to have happened, but I 'm happy to agree that we could do with a lot less conformity and a good deal more criticality.

Certainly the image of the 70s Marxist, quoting Althusser while concentrating his (for it is a he) energies on bed-hopping and quaffing red wine has some resonance. But is there any reason to suppose that cannabis use is more distracting, more soothing and placatory than any other activity capable of filling the secondary role in the 'bread and circuses' schema?

Not really. It is not true that cannabis makes people generally lazy and feckless. This is certainly something that may happen while stoned - just as with several pints on a Sunday afternoon. There may be some confusion caused by the fact that the only very visible dope-smokers tend to be those who are, well, visibly doped. And of course the lazy and feckless may well fill their lazy and feckless hours with an activity like smoking weed, or drinking booze.

But those who don't smoke large quantities - and possibly, those who smoke strains with low cannabidiol content, such as the demon skunk - aren't sedated. And the effect of cannabis at moderate dosage is to make one more sensitive to many things. On this regard, the operation of cannabis is almost exactly opposite to that of alcohol, which is a central nervous system depressant and turns people into increasingly crass, insensitive idiots. The 'paranoia' that sometimes affects some people on cannabis is a matter of over-sensitivity to others, of excessive self-consciousness, shyness, suspiciousness. This is a good thing. There has tended to be a general shortage of suspiciousness, of politicians, of business interests, of the permanent state, and of just about every other powerful interest.

The mass media, the ridiculous barrage of quietist propaganda churned out by the likes of David Aaronovitch, are the real source of a mindless, history-less, dissent-free society - but rather than a hideously calm dystopia, this is a mundane reality. Received opinion, the opinion of the privileged is that everything is going perfectly well thank you very much and only misfits think anything seriously corrupt or vicious is afoot. (This irrational insistence seems impervious to the constant stream of evidence that tells us otherwise.)

This is relevant in the context of my remarks two posts back, regarding the harms that can come from cannabis. There I mentioned that some transient effects of cannabis can be classified under the heading 'psychotic symptoms'. Note that checklists of psychotic symptoms tend to include such items as 'suspicion of others' and 'having ideas that others do not share'.

I am happy to own up to those two, with suitable qualifications, for which unfortunately there is no space on computerised diagnostic checklists.

If cannabis has a slight tendency to prompt original thought and to overcome complacent and misplaced trust, the influence of one of its opponents - big pharma - tends to work in the other direction, by way of drug prescriptions for low-level psychiatric diagnoses.

Psychiatry is important and useful. Alzheimer's disease, senile dementia, chronic schizophrenia, bipolar disorder and other major well-defined conditions, have devastating effects on many people and on their families. But other psychiatric diagnoses are less clear-cut, and have a nasty tendency to border on social engineering. One need not speculate about the extent to which psychiatrists, or perhaps more germanely, GPs making psychiatric diagnoses and prescriptions, share the complacent attitude described above and treat dissenting opinion accordingly. That is not the point: the very logic of individual psychiatric treatment is that society at large is a given, and the individual's well-being is a matter of adapting - conforming - adequately comfortably to that Leviathan.

An eminently sane unhappiness and alienation from society can easily become a 'symptom' (that is to say in this context, one of a group of items on a scored checklist) of some invented 'dysphoria' or other. When failure to fit in to society, a felt malaise, an unwelcome inability to adjust to social conditions, rather than any more objectively ascertainable criterion of mental illness is used, the aim of making people 'well-adjusted' rapidly converges with that of creating docile and compliant citizens.

But isn't this 'whataboutery'? Why point the finger at the quietist media and the potential problems of too-easy diagnoses of neurosis? Because I think not only that any influence of cannabis pales into insignificance by comparison with them, and with alcohol and vacuous entertainment on the telly, but also that if anything, cannabis tends to cut against these influences, by stimulating unconventional thought, indeed any thought, and - if my line of argument thus far is sound - by displacing antidepressants and so on as a source of consciousness-alteration.

(By the way, surely the career-minded networkers of New Labour are very much of the literal 'don't inhale' persuasion, while only a proper Charlie would suggest that the Cameroons tend to be partial to the weed?)

I don't necessarily claim that the effects I rather tentatively suggest are very strong. Even if those who use cannabis tend if anything, to be more likely to adopt positions that are in opposition to authority, this association, if real, may of course be an artefact of the current prohibition regime - unconventionality might explain a willingness to take illegal substances, or rebelliousness night be stoked by finding one's choice of drugs criminalised. I would certainly, in any case, maintain that cannabis is not the Soma Hitchens thinks it is.

And in the end, all this has little relevance to the legalisation debate. The idea of social engineering to ensure freedom has an oxymoronic quality about it. Increasing liberty does not mean forcing people to act in a way which will maximise their future tendency to exercise liberty in a certain way. Freedom includes the freedom to do nothing, and to do things which some might consider make one less free. Overriding freedom of action for the sake of a claimed greater future freedom may perhaps be justified - depending on how absolutist one wants to be about simple freedom of action - but it had better be well-justified. Hitchens does not provide a suitably strong justification. In other words, if cannabis use means 'soft totalitarianism', still better that than the alternative - the hard totalitarianism of unrelenting prohibition.

There is another way in which the banning of drugs in general, and of the most prevalent of them, cannabis, is relevant to freedom, which relates to the points made some yards further up this post, concerning drug enforcement efforts inevitable intrusion into the private realm. The War on Drugs, like the rest of the unbroken lineage of phoney 'wars' that includes the earlier Cold War and the current favourite, the War on Terror, has performed two major functions - overseas, to provide cover for military 'interventions', and on the domestic front, to justify ever greater incursions into civil liberties. If one cares about liberty, one had better think very carefully about endorsing drug prohibition.

Having dealt at some length with policy matters, I'll defer discussion of more purely moral issues to a separate post, to follow shortly.

29 comments:

Tim (if I may call you that), could you discuss at some point the impact on crime, if any, which legalisation would have? I don't think you have already, but I might be mistaken. It's surely a crucial point.

Particularly, I'd be interested to know what you make of the prohibitionist counter-argument that it wouldn't reduce crime, since cannabis dealers would just move into areas. This is something I've been discussing with a contributor at PH's blog.

Avoiding any contentious hypotheses, I'd say that removing an income stream without introducing another would hurt criminal gangs, and presumably lead to redundancies.

Redundant cannabis gardeners don't seem a big threat- and might be able to go straight without changing profession. Financiers, bosses, distributors, etc, and those engaged in smuggling might try to find other illegal income sources, but I suppose they would basically be in the position of any other aspiring criminal generalist looking for a niche.

Actual low-level cannabis dealers I wouldn't think would normally have any transferable criminal skills or assets, beyond perhaps basic security, police connections which are unlikely to be useful for 'proper' crime, that kind of thing. I suppose some professional cannabis dealers with a long CV gap and no skills or sufficient savings might find that petty crime would be one of their few options - maybe knocking out moody goods at car boots, that kind of thing.

I think the problem of what to do with the newly unemployed comes under imaginative solutions to transitional problems.

In any case, I don't think anyone is suggesting that legalisation would cause a huge drop in effective demand, so presumably at least some new jobs would be available, depending on the exact form regulation took (for example, if cannabis could only be sold in outlets analogous to sex shops.)

All this is just off the top of my head really - though based generally on some background research for which I can't give chapter and verse. I may take a closer look if it turns out PH has raised or does raise the issue.

Tim, thanks for the reply. I write this having just consumed a fair amount of the legal drug alcohol, hence the ungodly hour of my reply, and the lack of coherence, if any. What relevance my inebriated state has to the debate I don't know.

I suppose some cannabis dealers might be tempted to move to the sale of other drugs, which probably wouldn't require any further skills. But this might be just an argument for the legalisation of all drugs.

Evidence from the Netherlands and Portugal seems to suggest that legalisation would lead to a decrease in demand. But this is counter-balanced by contradictory evidence elsewhere. Either way, I think we can both agree that legalisation wouldn't lead to a huge increase in demand, as prohibitionists tend to fear. And I agree that it would be a more benign drugs market, and one which would contribute positively to the economy and government revenue.

Essentially, I agree with you, and I think your response deals with the crime argument much better than I have, with considerably fewer words.

I draw readers attention to this rather misleading intervention by Prof. David Nutt re Peter Hitchens: http://www.guardian.co.uk/commentisfree/2011/jul/21/review-bbc-science-coverage Readers should listen to the original Radio 4 broadcast (there's a link at Peter Hitchens' site somewhere).

I see we are rehashing that 'Today' and 'Feedback' story from a while back, I'm not getting into it on Hitchens' blog because it's, as I said, just a rehash

I listened to it then and also encourage people to find it now - as much as Nutt's report is open to question, he is completely right that Hitchens harangued and talked over him - his defence of that behaviour was that he 'knew' how the BBC would run the show and decided to get himself a fair hearing and get the last word in, as he 'knew' he wouldn't get it

Unfortunately he never let us prove this theory, and it did nothing to scrutinise Nutt, it's not surprising he came out looking worse

But Nutt portrayed himself as a scientist merely offering scientific data. He wasn't - he was recommending social policy. PH may have harangued a bit - not a great crime when time is limited and it's difficult to get in - but he made some valid points re the very general and rather unscientific 'social harms' claims made by Nutt. Given that 'science' is accorded such respect by the interviewer, this was perfectly valid. PH explained his stance on the subsequent Feedback segment - I've yet to see Nutt rebut any of them. He had a chanvce with his Guardian article - he didn't even discuss his paper - merely wrote a number of falsehoods (see PH post).

Nutt was recommending a social policy grounded in scientific evidence...

as Hitchens refuses to take the science into account, his comments can only offer more of the same self-referential hot air and prejudice

as such, Hitchens is very much on the margins of this debate, which is exactly where he belongs

a good piece Debunking the Myth of a Link Between Marijuana and Mental Illness, from July 25th, by Paul Armentanohttp://www.alternet.org/drugs/151776/debunking_the_myth_of_a_link_between_marijuana_and_mental_illness?page=1

and another welcome declaration from the National Association for the Advancement of Colored People on July 26th: NAACP says end the "war on drugs"http://copssaylegalize.blogspot.com/

would PH like to write a piece about the war on drugs and the mass incarceration of people of colour?

"Nutt was recommending a social policy grounded in scientific evidence... as Hitchens refuses to take the science into account, his comments can only offer more of the same self-referential hot air and prejudice"

Have you read that "scientific evidence" for yourself? Check it out. The full text is available for free download.

Everyone who is motivated to support Nutt should do this. They need to know what sort of work they are defending. I was most disappointed that my colleagues took Nutt's claims at face value and didn't bother to read his paper, even though they could easily have done so.

given your claims to an authoritative insight into this issue, why not take the time to enlighten us with just a couple of sentences and give some actual reasons as to why you regard Nutt's paper as unsatisfactory?

so far all we have had from you are unsubstantiated assertions... could it be you are nervous about engaging with the facts?

as is the case with Hitchens, the absence of any evidence-based reasoning with which to engage makes it very difficult to have a meaningful discussion with you

I have in mind your earlier claim, the one where you insisted you had read all of the literature on cannabis and mental health and found it point overwhelmingly to a link between cannabis and psychosis...

I can only reiterate: cannabis use is exploding worldwide, cannabis potency in the UK doubled in the last ten years, the "relative risk increase" doom-mongers such as Murray are flapping about, but where oh where is that cannabis psychosis epidemic? Found it yet?

some more research due to be published in the journal Addiction:

Long-Term Marijuana Use Not Associated With Deficits In Cognitive Performance, Study Sayshttp://norml.org/index.cfm?Group_ID=8637

I never claimed, much less insisted, to have read all the relevant research. Be fair.

If you've read that paper and are genuinely satisfied by it, then there's really nothing more that I can do for you. As a hint, though, the aspect that bothers me most is the source of the data. Where have all these relative harm scores come from? Find the answer to that question and you've discovered the key problem with the paper.

Incidentally, I should point out that Andreasson's paper "Cannabis and Schizophrenia: A Longitudinal study of Swedish Conscripts" was also published in The Lancet. Why trust one paper and not the other?

I'm not aware of having explicitly rejected the Swedish paper. My line is that even if there is some bordering-on-negligible risk that cannabis may cause psychosis in a tiny fraction of uses, this could never constitute a rational reason for prohibiting cannabis, as there is no evidence whatsoever that such laws result in a limiting use, let alone decreasing it...

the one million new regular and occasional cannabis users recorded in the last five years in a French parliamentary report in June, for example, illustrate this nicely

if psychosis is of genuine concern to you then there are more intelligent legislative options that would allow a more thoroughgoing control over the point of sale than blanket prohibition ever can

it's a pity really, you had seemed so willing to engage in protracted and detailed discussion of 'relative risk increases'...

why such reluctance to engage in other areas of debate?

perhaps instead you'd be happy ranking the following popular activities in what you believe to be the order that best reflects their respective risks:

swimmingcosmetic surgerycannabis smokingskiingcoffee drinkingstaying up all nightoh, and last but not leastcar driving

if it turns out that cannabis smoking isn't the riskiest of those activities, then perhaps you could explain to me why it is that cannabis smoking alone should be banned?

coffee drinking and not sleeping enough are alleged to be a cause of psychosis - do you believe the gov't should also ban them?

or is it that there is something about cannabis use that makes it exceptional?

could it be that you just don't like it anymore?

or should we also ban not sleeping enough, caffeine, and perhaps swimming too?

if not, then I'm afraid I will have to conclude that your inconsistency betrays your prejudice and hypocrisy, and that you are indeed a fitting ally of Mr. Hitchens

Actually I never stopped liking the drug. I would love to be able to brush aside all the concerns and indulge once more. And sometimes it is tempting. But the need to resist is stronger.

I know you're just itching for a lecture on rights and responsibilities, on moral absolutism and "do unto others", but what would be the point? All anyone can do for you right now is encourage you to doubt your certainties and think about things more carefully. In this society, which effectively encourages you to use drugs, there is nobody to save you from yourself. It is all up to you.

I'd appreciate it if you would have the courtesy to respond directly to the points I'm making, as I'm sure other people reading this would

I'm honestly looking for nothing more than a rational, evidence-based response in which you engage directly with the arguments I'm putting to you...

evidently my contention here is that there are a host of commonplace activities in which ordinary people engage that are far, far riskier than using cannabis...

I may of course be wrong, hence why, given your evident concern about the risks of using cannabis, I'm inviting you, once again, to chose a list of commonplace activities and rank cannabis smoking along with them in terms of risk - providing reasons, of course

you are welcome to chose a list of your own, whatever you think would be most meaningful and illustrative...

as you believe cannabis is genuinely dangerous, I assume the activities among which you list will also be dangerous...

an appropriate list might then be something such as

playing rugbycooking and preparing foodbicyclingwalking up and down stairsswimmingcosmetic surgeryskiingcoffee drinkingstaying up all nightcar driving

I hope you will take the time to do that, and provide reasons for the placing you giving cannabis

Omit cannabis and try to put the other activities into an ordered list yourself, and you'll see what a silly exercise that really is, because the list items are not comparable. They involve not only different *levels* of risk but also different *types* of risk. And cannabis is a *type* of risk quite unlike anything else on the list.

In the sports you list, accidents happen, sometimes fatal, sometimes causing brain damage. But because these happen (1) accidentally, rather than as an essential part of the sport, and (2) immediately, rather than as an imperceptible decline, they are completely unlike the *type* of damage done by cannabis.

The problem appears to be that you are not thinking about this in a sufficiently abstract way. You are all about risk *level*, when you should be thinking about risk *type*. This trick may win you debates, but it does not make you right, and I think it will only convince people who want to be convinced.

"You are all about risk *level*, when you should be thinking about risk *type*."

I'm not much of a cannabis smoker, I prefer to eat it, and other than the risks involved in smoking any burning plant matter, I'm not aware of any serious types of risk for cannabis at all, other than the controversial claims about psychosis

and so far as cannabis causing psychosis goes, the risk level is obviously always relevant, precisely because it is negligible - and even the pro causation papers are explicit that the risk of psychosis from using cannabis is negligible

Glyn Lewis, Professor of Psychiatric Epidemiology at the University of Bristol reviewed all published research on cannabis and psychosis in 2009 and concluded that 96% of people are at no risk of psychosis whatsoever when using cannabis --- he concluded that in the remaining 4% the risk is “statistically tiny”

this isn't, as you say, a "trick" to win a debate, it's about being clear

You're not aware of any serious types of risk? Perhaps you just choose not to see them. Firstly, Glyn Lewis is probably wrong, but not just because his conclusion contradicts others (notably the Swedish conscripts study). There is also the likelihood that other sorts of damage are done by the drug, which have not been considered by Lewis or the other researchers. It is well-known that there is an impact on intelligence, memory and concentration within about a week of the last usage, and of course this will have an effect on everyone around the user: friends, family, colleagues. Long-term effects seem likely as well, and maybe you can think of a few people in your own life who may have been affected in this way. People who were once smart and healthy, and now have trouble concentrating and are perpetually anxious and neurotic. Look closely, you probably know a few like this. Maybe even yourself.

And I was careful not to mention smoking! (I know that debating trick, too; talk a lot about smoking, get the other side to explicitly refer to smoking, and then say "ahbutyoudonthavetosmokeit", thus distracting from whatever they are actually saying. Very clever.)

it's understandable really as there are numerous difficulties for extremists -

first of all there is the absence of any psychosis epidemic or any other known endemic health issue correlating with the explosion in cannabis use in the West since the '60s

then there are the rafts and rafts of papers contradicting your positions, such as the Australian paper published in Addiction this month

Long-Term Marijuana Use Not Associated With Deficits In Cognitive Performance, Study Sayshttp://norml.org/index.cfm?Group_ID=8637

then there's the fact that the overwhelming majority of the people reading this will simply be unable to find anything in their own life matching the terms of reference you use

you refer to "People who were once smart and healthy, and now have trouble concentrating and are perpetually anxious and neurotic. Look closely, you probably know a few like this. Maybe even yourself."

I'm doing just fine thanks Julia, I'm in rude health, very relaxed, and my powers of concentration and memory are excellent... I recently finished memorising a Khmer script, for example

I've been an occasional and/or regular cannabis user since the age of about 16 or 17, with several breaks of more than a year while I worked in the Far East

I have an MA/BA from Oxford University, and another MA from Bristol - five years ago I started my own business, one year ago another, and both have been growing very successfully ever since

my oldest mate is a regular smoker and a successful journalist, fluent in Russian, who recently completed an award-winning 600 page book on the Caucasus; his wife, also a regular cannabis user, graduated with a double first from Oxford in Medicine (as well as Fine Art) and currently works in the NHS, in mental health services

of my other friends and family, many are cannabis users - I could point you to lawyers, teachers, medics, authors, scientists and businessmen - none of them the mentally ill burned out wrecks you refer to, and all of them notably successful

it may not be easy for you, but I think you need to come to terms with the fact that no matter how much disingenuous panic-mongering is thrown at them by Murray, Hitchens and Mary Brett, the rest of the world has every right to make an informed decision to use cannabis, whatever the risks, however great or small, if they so choose to do so... choose they have, and choose they will

I could claim similar things, since I used it most heavily while writing up my PhD thesis, and throughout my first degree as well.

So why don't I? There's a puzzle. You say there is all this scientific evidence that it's perfectly fine, and I say I'd like to believe you. Yes, like Fox Mulder, I want to believe. But I don't, and I can't, because there are dozens of good reasons *not* to use the drug, and no good reason to use it.

Articles like the one you link just emphasise the sort of damage that the drug could be doing within someone's brain. It would be incredible if all of these beneficial effects came with no downsides... incredible in the "free energy device", "homeopathic medicine" or even "Victor Meldrew" sense, as in "I don't believe it". It was once thought that LSD was a good way to expand your mind... then the irreversible brain damage was discovered. Same thing here. Everything has a cost.

The quality of Julia's comments has, like Hitchens's, gone desperately downhill from what appeared a reasonable enough start. Just in relation to the last couple of comments:

1. I'm not impressed with Julia's attempts to award herself special authority by claiming to 'want to believe', telling us she was a heavy user, and reporting anecdotes about the devastating effects of cannabis use.

Anecdotes are unuseful as evidence in many contexts, including this one, because they are selective single cases rather than statistics, but also because they are testimony, often incorporating conclusions which the witness is unqualified to reach.

The testimony of an anonymous commenter, perhaps especially one who obviously has a strong opinion, is worthless.

In fact, since a lot of it is insinuation and operates at a very Hitchens-like sub-rational level, I'd actually suggest that the best way of neutralising the illicit influence of Julia's comments is to assume she is lying.

(Angus has supplied testimony too - and I don't accept that as good evidence either, though it is at least quite specific and non-manipulative. He is also entirely justified in offering it in response to Julia's remarks.)

2. it is well-known that, etc., is not good enough. Some kind of citation - preferably a url or hyperlink - is, as they say, needed.

3. It is clear that there is some serious - almost feverish - thought going into the tactics of these apparently frank and off-the-cuff remarks:

I was careful not to mention smoking! (I know that debating trick, too; talk a lot about smoking, get the other side to explicitly refer to smoking, and then say "ahbutyoudonthavetosmokeit", thus distracting from whatever they are actually saying. Very clever.)

Note though that this is all projection - Angus didn't do anything of the sort. All he does is to mention - and acknowledge - smoking risks, and distinguish them from risks of cannabis use per se.

4. The stuff about 'risk level' and 'risk type' is rubbish. In a cost-benefit context, you have two factors - how good or bad an outcome is, and how likely it is to occur.

What the 'risk type' is supposed to be, since it is evidenctly mean to be distinct from both the magnitude and the probability of a certain harm, is entirely unclear. In any case, neither of the grounds suggested - even if they could be shown to be relevant - would distinguish cannabis from sport: (1) supposed harms of cannabis occur 'accidentally', rather than as an essential part of the sport, and (2) sporting injuries do not necessarily occur immediately, but very often take the form of cumulative damage to joints etc.

But as in some of the posts in this series, even by bothering to rebut it I have the feeling of according a half-baked idea far more credence than it really merits.

5. It would be incredible if all of these beneficial effects came with no downsides...Everything has a cost.

Therefore, if cannabis has some benefits it must impose a substantial risk of harm? This has the appearance of magical thinking, a bit like Hitchens's idea of a fixed maximum amount of enjoyment available over a human life.

Risk *type* was introduced by myself to counter Angus' transparent attempt to argue for an ordering based on risk level that favours his strong opinions about legalisation.

Is this not "entirely justified" in response to Angus's comments?

I was arguing that risks of different types are not comparable, which is self-evident. It is perfectly clear what "risk type" is. It refers to the mechanism by which harm is caused. The risk of lung cancer from smoking is entirely different to the risk of death in a car crash, is it not?

Is driving more dangerous than smoking? The question is nonsense. You have no way to put the two types of risk on the same scale.

I'm asked for a reference for my claim that "It is well-known that there is an impact on intelligence, memory and concentration within about a week of the last usage, and of course this will have an effect on everyone around the user".

I'd thought this would be unnecessary as Tim Wilkinson has himself stated that "Habitual cannabis use during the school day, is certainly going to interfere with learning, for example". He provided no source for that.

However, my source is Iversen, "Long-term effects of exposure to cannabis" (Current Opinion in Pharmacology, 2005, 5:69-72), which includes the following:

"It is not sufficient to identify a group of cannabis users and simply to test them after stopping cannabis use. One study, for example, recruited 63 current heavy users who had smoked cannabis at least 5000 times in their lives and 72 control subjects [3]. The subjects underwent a 28-day washout from cannabis use, monitored by urine assays. At days 0, 1 and 7, the heavy users scored significantly below control subjects on a battery of neuropsychological tests, particularly in recall of word lists. However, by day 28, there were no differences between the groups in any of the test results, and no significant association between cumulative lifetime cannabis use and test scores. The fact that drug-induced effects on cognitive performance can persist for up to a week after stopping the drug (perhaps because of the persistence of D9-tetrahydrocannabinol [THC] in the body, or because of a subtle withdrawal syndrome) means that many earlier studies that did not allow a sufficiently long washout period might be invalid."

This debate has been characterised by its asymmetry. Tim Wilkinson does not need to provide sources, but his opponents must. His supporters can have "strong opinions", but his opponents cannot. He can use anecdotes, such as:

"many who take cannabis report that they experience an enhancement of creativity or of the ability to concentrate"

But his opponents are attacked when they talk about their own experiences. Positive views of cannabis use, such as "stimulating unconventional thought", are acceptable. Negative views of cannabis use, such as the ones described by myself, are to be treated as follows:

"I'd actually suggest that the best way of neutralising the illicit influence of Julia's comments is to assume she is lying."

I have contributed to this debate in good faith. This sort of rudeness is uncalled for. If you like "unconventional thought" so much, why do you attack people such as myself when we express it?

On sources, thanks for supplying yours. It makes it possible to point out how small the effect was, and clarifies the fact that the supposed impact on family is your own conclusion.

I accept that my "many report..." stuff - I think this was from my opening remarks? - is inadequate on its own to establish a point. I have expanded on it somewhat since, and had intended to go further had Hitchens not pulled the plug, and especially if he had challenged my assertion as I've challenged yours (admittedly in an unnecessarily didactic and condescending tone).

I think my own claim wore its inconclusivity on its face, though - this is different from referring to what looked like (and, it turns out, was) a very specific scientific result as 'well-known', which is to lay claim to a far greater authority than my remarks did.

The other remark of mine that you quote, about schooling, was in the nature of an admission - which doesn't require supporting evidence. My case didn't by any means rely on the assertion, and indeed I suppose I wouldn't have made it were I single-mindedly trying to press my own case.

On unconventional thought, though: Just to clarify, it's good to have unconventional thought around, but a lot of it is wrong and some very nasty (I'm talking generally here, no reference to you.)

I wouldn't classify your comments as manifesting unconventional thought anyway, and certainly didn't 'attack' you on such a basis. I don't measure the quality of opinions by whether they are conventional.

Regarding rudeness, my comment recommended a methodological assumption. I didn't accuse you (whoever you may be) of lying.

But I should probably havetried to put it in other terms, and I'm sorry in general for the tone of that comment, which could have been less confrontational. I think you may have borne the brunt of some residual irritation at Hitchens's failure to engage.

Actually I think I may not have taken that claim - about creativity etc. - further yet. If not, I was probably thinking of some comments in a draft final post that I've been toying rather desultorily with.

I still think that "risk type" makes sense. Comparing the risk from cannabis to the risk from, say, a car crash is rather like comparing weight to distance. The damage done is of a wholly different sort, so the two cannot be placed on the same scale. To invent some arbitrary figures, say the risk of brain damage from cannabis is 12.6 metres, and the risk of death in a car crash is 98.7 Watts. Which is worse?

In reality, the units of these measurements could not be metres or Watts, but they would nevertheless be different to each other, and hence incomparable. With driving, we should ask how often someone drives, in what sort of car, in what conditions, over what distance and with what level of skill. With cannabis we would be interested in dosage, frequency of use, CBD/THC content and so on. These measurements would have no analogy for driving.